Adjusting system for field glasses



June 9, l942 J. A. v. BENARD 2,285,388

ADJUSTING SYSTEMS FOR FIELD-GLASSES Filed Jan. 50, 1940 5 Il n, [nl

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Patented June 9, 1942 ADJUSTING SYSTEM FOR. FIELD GLASSES Jacques Alfred Victor Bcnard, Paris, France Application January 30, 1940, Serial No. 316,399

In France February 1, 1939 iclalms.

The present invention relates to prismatic or other eld glasses of the type comprising two eye-pieces, each of which is associated with a body with which it is compelled to remain coaxial and which carries the other elements of the optical system, the focussing being effected by rotating a wheel which is located in the medial portion of the apparatus and responsive to which the two eye-pieces are simultaneously `moved parallel with each other.

In such field-glasses, the distance between two eye-pieces is preferably adjustable, in general by rotating one unit formed by an eye-piece and a body relatively to the other similar unit about the medial axis of the field-glass, so as to enable the latter to be adjusted to the distance between the eyes of the observer.

The present invention has for its main object a novel system of improved adjustment -for eld-glasses of the aforesaid type, aiming at improving the guiding and making the focussing movement more accurate.

A further object of the invention is to concentrate at one and the same region of the lleidglass all the indications required by an observer and, for this purpose, according to an advantageous embodiment of the invention, a mark which is xed relatively to one of the two arms of the group or of one group of xing arms for the eye-piece holders co-operates with a graduation engraved on a part that rotates integral with said tube nut, and with a graduation secured to the other arm of said group.

The first graduation, which is in diopters for example, is intended for-focussing the iield-glass and the other graduation enables the ocular distance to be adjusted, so that a single reading,

by means of a single index, enables the instrument to be adapted to the characteristics of the observers eyes.

Other features and objects of the invention will moreover become apparent from the ensuing description taken with reference to the accompanying drawing which is given solely by way of example and in which:

Fig. 1 is a sectional elevation of the medial portion of a eld-glass according to the invention, the eye-piece holder and lens-holder systems being removed;

Fig. 2 is a corresponding perspective view of the upper part of Fig. l;

Fig. 3 is a similar view to Fig. 2 of a modication.

According to the embodiment shown, the ileldglass is the type comprising two eye-pieces each associated with a body with which it is compelled to remain coaxial and which carries the other elements of the optical system, the i'ocussing being effected by simultaneously moving the two eye-pieces parallel with each other.

The body and the eye-piece of the held-glass according to the invention may be constructed as usual; these parts and their support have not been shown inorder to simplify the illustration, and one of the two bodies is secured to the arms land 2 and the other to the arms 3 and I, and the two eye-pieces are respectively xed to the arms 5 and 6. These groups of arms respectively form three hinges, the common axis of which .Is materialized by a central rod 8. Said rod terminates in a head 9 on which rests the arm I ilxed thereon by a screw III and said head acts as a support for a tube I2 forming a hinge screwed to the rod 8 at its end immediately above said arm I. It is on said tube I2 forming a hinge that are mounted the arms 3 and d by means of the bracing tube I3 connecting them together and fixed by screws I4 to the arm I, and the arm 2 held between the arm l and a turned over ange I5 which terminates said tube I2 forming a hinge. Inside the hinge-tube I2, the rod 8 is provided with a portion of smaller diameter I6 and terminates in a multiple thread Il at the end of which is mounted a stop screw I8. A tube nut 20 fitted in the hinge-tube I2 is provided with internal threads co-operating with said multiple thread I1. The tube nut 20 projects from said hinge-tube I2 and terminates in a cylindrical head 22 on which are mounted the two arms 5 and 6. The arm 6 bears on a turned over ange 23 at the end of the head 22. The arm 5 is arranged between the arm 6 and an abutment surface provided by the wheel 25 which is secured to the tube-nut 20, by means of a screw-thread 21 and a stop screw 28.

The head 22 of the tube nut is surmounted by a knob 3D fixed thereto by means of a screwthread 3l and a stop screw 32.

As shown in Fig. 2, the arm 6 carries a mark 34 opposite which graduations 35 in diopters or the like are engraved on the knob 30, and graduations 3l for the ocular distance are engraved on the arm 5 which is provided with a surface shaped for this purpose.

The rotation of the wheel 25, which is imparted by hand, drives the tube nut 20 which engages the screw-threads I1 and causes said tube to move the assembly of the arms 6 and 8 which are ilxed to the eye-pieces more or less 55 far away from the arms I to 5 which are ilxed to the body of 4the field-glass and enables the focussing to be effected accurately.v The wheel 25 participates in the translatory movement of the eye-pieces. contrary to what takes place in the usual field-glasses. The arrangement of the tube nut 20 and of the multiple screw-threads I1 ensures a very long guiding of said tube nut in the tube-hinge l2, the screw-threads being` perfectly protected and being, owing to the novel arrangement, of minimum length.

n the other hand the knob 3,0 participates in therotary movement of the tube nut 20 and the graduation 35. which is generally in diopters, enables the adjustment division for the instrument which is suitable for the observer to be read opposite the mark 34. graduation 31 enables the division for the ocular distance which suits the observer to be read opposite this same mark 34. A' single reading effected in one and the same region of the instrument is, consequently, sufficient to enable it to be adapted to the characteristics of the observer.

Fig. 3 shows a modification of the upper part ofthe apparatus showing another'embodiment of the novel system of centralized adjustment that can be obtained by means of the construction according to the invention.

Referring to this figure, the graduations 35 in diopters or the like corresponding to the focussing of the ileld-glass are engraved on the upper -facevof the wheel 25 or of a part tted on the wheel and cooperate with an index 34 provided on the lower arm 5. It is opposite this same index that the graduations 31 of ocular distances are engraved on the lateral central part of the upper arm 6, so that the adjustment is effected in a single reading, as explained with reference to the previous example.

0f course, the invention is in no way limited to the embodiments illustrated and described which have only been given by way of examples.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification, withoutdeparting from the spirit of the invention. I therefore do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

What I claim is:

1. In eld glasses, a central rod having threads thereon, a head carried by said rod, a body arm mounted on said head, a hinge tube secured to and surrounding said central rod, a bracing tube surrounding said hinge tube, a second body arm mounted on said bracing tube adjacent the first body arm, a third body arm mounted on said bracing tube and spaced from the second body arm, a fourth body arm pivotally mounted on said hinge tube adjacent the third body arm, a nut tube extending into thev hinge tube and Furthermore, the

threaded on said central rod, a hand wheel secured to said nut tube, and two eye-piece arms pivotally mounted on said nut tube to move therewith.

2. In field glasses, a central rod having threads thereon, an integral head carried by said rod, a body arm mounted on said head, a hinge tube threaded on and surrounding said central rod in a spaced relation, a bracing ,tube surrounding said hinge tube and rotatable thereon, a second body arm mounted on said bracing tube adjacent said flrst body arm, a third body arm mounted on said bracing tube and spaced from the second body arm, a fourth body arm pivotally mounted on said hinge tube adjacent the third body arm, a nut tube extending into the hinge tube and threaded on said central rod, a hand `-whee1 secured to said nut tube, a flange carried by said nut tube, and two eye-piece arms pivotally mounted on said nut tube between said flange and said hand wheei so as to move with the nut tube.

3. In field glasses. a central rod, a head carried by said rod, a body arm mounted on-said head, a hinge -tube threaded on and surrounded by said central rod in a spaced relation, a bracing tube surrounding said hinge tube and rotatable thereon, a second body arm mounted on said bracing tube adjacent said head, a third body arm rigidly mounted on said bracing tube and spaced from the second body arm, a flange carried by said hinge tube, a fourth body arm pivotally mounted on said hinge tube between said flange and the third body arm, a nut tube extending into the hinge tube and threaded on said central rod, a hand wheel secured to said nut tube, and two eye-piece arms pivotally mounted on said nut tube so as to move therewith.

4. In eld glasses, a central rod having threads on the periphery thereof, a head carried by said rod, a body arm mounted on said head, a hinge tube secured to and surrounding said central rod in a spaced relation, a bracing tube surrounding said hinge tube and rotatable thereon, a second body arm mounted on said bracing tube adjacent the rst body arm, means carried by the bracing tube maintaining the second body arm adjacent the iirst body arm, a third body arm rigidly mounted on said bracing tube and spaced from the second body arm, a fourth body arm pivotally mounted on said hinge tube adjacent the third body arm, a nut tube extending into the hinge tube and slidably guided therein, internal threads carried by said nut tube engaging the threads on said central rod, a hand wheel secured to said nut tube, a flange carried by said nut tube, and two eye-piece arms pivotally mounted on said nut tube between said flange and said hand wheel.

JACQUES ALFRED VICTOR BENARD. 

